Abengoa is committed to solar thermal power and has pioneered development in tower and parabolic trough technologies. With regard to solar power alone, currently the company has an installed capacity of 2.3 GW  in operation worldwide.

1. Solar Thermal Energy:
I. Parabolic Trough Technology
II. Tower Technology
1

2. Index
1 Introduction
2
3
4
2
Solar Thermal Technology:
Dispatchability as a Stand-out
Element
Parabolic Trough Technology
Tower Technology

3. Introduction to Solar Irradiance
3
Irradiation coming from the sun goes through
the atmosphere generating:
• Direct Normal Irradiance (DNI), which comes to the
earth directly. It has a well defined trajectory, and
because of its quality as a vector, can be
concentrated.
• Diffuse Horizontal Irradiance (DHI), which has a
modified irradiance direction. DHI doesn’t have a
defined trajectory, therefore it can’t be concentrated.
• Global Horizontal Irradiance (GHI), which is the total
amount of irradiation that the horizontal surface of
the earth receives.
Direct
Diffuse
Global = Diffuse + Direct
Direct Direct
on horizontal plane
on normal plane
Direct
Diffuse
Global = Diffuse + Direct
Direct Direct
on horizontal plane
on normal plane

4. Distribution of Direct Normal Irradiance (DNI)

5. Index
1 Introduction
2
3
4
5
Solar Thermal Technology:
Dispatchability as a Stand-out
Element
Parabolic Trough Technology
Tower Technology

6. Differences in Dispatchability:
6 For electric companies, biomass and STE are the only
sources of manageable renewable energy

7. Four Main Solar Thermal Technologies
7

8. Index
1 Introduction
2
3
4
8
Solar Thermal Technology:
Dispatchability as a Stand-out
Element
Parabolic Trough Technology
Tower Technology

9. A Parabolic Trough Plant
9
Power Block
Solar Field
Solana, la mayor planta cilindroparabólica con almacenamiento del mundo (Arizona, EE. UU.)

10. Scheme of a Conventional Parabolic Trough Plant
10
Evaporator

11. Sections and Components of a Parabolic Trough Plant
11
Solar Field
Storage system
Collector
Power block

12. Solar Field
12
A group of parabolic trough collectors capture the
solar energy and carries it to the power block, where
the heat energy is used to produce steam

13. Parabolic Trough Collector
13
Parabolic trough collectors concentrate solar irradiation onto a
point or line where the receiver is situated. It transfers the heat to
the Heat Transfer Fluid (HTF).
The parabolic trough collectors are organized in lines and oriented
towards north and south, so they follow the sun on one axis
The main elements of a parabolic trough collector are:
• Foundation and support frame
• Reflective surface
• Absorbent tubes
• Track system
• Hydraulic system
• Instrumentation and control

14. Parabolic Trough Collector
14
• A complete parabolic trough collector is formed by 10 or
12 modules.
• A collector module is formed by 28 mirrors (4 lines and 7
columns).
• Parabolic trough collectors are coupled in loops in order
to keep a continuous heating process in each plant. A loop
is formed by 4 collectors.

15. Parabolic Trough: Reflective Surface
15
• A group of mirrors of glass-metal technology made with a parabolic shape.
• The reflectivity of these mirrors is higher than the 92% for the wavelengths that compound most of the solar
irradiation spectrum.

16. Absorbent Tubes
16
The absorbent tube is one of the most important elements in every parabolic trough collector. It is
formed by these elements:
• The absorbent tube which is made of stainless steel, with a selective coating where the Heat Transfer Fluid (HTF) circulates.
• A glass tube with an non-reflexive coating for a better solar transmission. The vacuum between the absorbent tube and the glass
tube eliminates the heat spread.
• Dilatator (bellows) absorbs the thermal expansions.
• A Getter maintains the vacuum.

17. Power Block
17
Turbine
Storage tanks Cooling tower Water treatment plant

18. Examples of Parabolic Trough Plants
18
Solana
• Arizona, U.S.
• 280 MW
• 6 h molten salts storage
• Parabolic trough technology
• Operational since 2013
• A Getter maintains the vacuum.
Solar Extremadura Complex
• Extremadura, Spain
• 4 plants of 50 MW
• Parabolic trough technology
• Solaben 2 & Solaben 3: operational since 2012
• Solaben 1 & Solaben 6: operational since 2013
KaXu Solar One
• Northern Cape, South Africa
• 100 MW
• 2,5 h molten salts storage
• Parabolic trough technology
• Operational since 2015

19. Index
1 Introduction
2
3
4
19
Solar Thermal Technology:
Dispatchability as a Stand-out
Element
Parabolic Trough Technology
Tower Technology

20. Scheme of Tower Plants
20
Molten Salt Tower Super-heated Steam Tower

21. Scheme of a Parabolic Trough Plant
21
Power Block
Solar Field
PS10, the world’s first operational commercial tower

22. Scheme of a Parabolic Trough Plant
22
Solar Field
Storage System
Receiver
Power Block

23. Solar Field - Heliostats
23
Heliostat: a mirror mounted on a dual-axis structure rotating
clockwise, capable of redirecting solar irradiation on one point.

24. Solar Receiver
24
Receiver System
The solar receiver is located on the highest part of the
tower where the solar energy is concentrated. In this
point, the steam can be directly generated or a Heat
Transfer Fluid (HTF) can be heated up to later be used
for steam generation.

25. Tower Technology Components: Storage Systems
25
Different kinds of storage systems
There are usually two storage technologies at solar thermal tower plants. These are steam storage tanks, or, for a plant that
needs 3 or more ours of storage, molten salt tanks.
Steam storage tanks at Khi Solar One (Northern
Cape, South Africa). This allows this solar
thermal plant to produce 50 MW for two hours.
Thermal energy storage tanks in molten salts in
Solana (Arizona, U.S.). This system allows the
plant to produce 280 MW for 6 hours.

26. Tower Technology Components:
Power Block
26
PS20, la segunda planta
comercial del mundo, entró
en operación en 2009
Turbine
Storage tanks
Cooling tower
Water treatment plant

27. PS10 and PS20 are the World´s First Operational Commercial Towers
27
PS10
• 11 MW
• Storage
• Receiver’s technology: saturated steam
• Operational since June 2007
• 624 heliostats, of120 m2 each
• 6.700 tCO2 avoided per year
PS20
• 20 MW
• Storage
• Receiver’s technology: saturated steam
• Operational since May 2009
• 1.255 heliostats, of 120m2 each
• 12.100 tCO2 avoided per year

28. Khi Solar One: superheated steam tower
28
Characteristics:
• 50 MW
• Steam storage
• Superheater + 2 systems of evaporation
• Natural draft cooling system
• A 200 m high tower
• A 4120 heliostats solar field
• 19 steam storage tanks
Generation of superheated steam at the receiver
maximizes the efficiency of the technology.

29. Atacama 1: Molten Salt Tower
29
• Located at the Maria Elena commune, in the Atacama desert
• 110 MW of installed power
• Thermal storage system with capacity for 17,5 hours of production
• Capable of producing 24 hours a day
• Avoids the emission of 643.000 tons of CO2 per year
• Construction started in 2014
• Operation scheduled for 2017